Thank you. That's a great question because there are a lot of issues. People think, oh, it's a fuel-cell car. A fuel cell is simply a type of battery.
For a battery, the chemistry is inside the battery. We're all familiar with that. In a fuel cell, the chemistry is on the outside of the battery, usually in the form of hydrogen or natural gas—anything that carries hydrogen. You put the chemistry in and it makes electricity.
A fuel cell can be the size of a credit card. It can be the size of a laptop. You can scale it up for any application. It's simply a type of battery with the chemistry on the outside.